I have posted about IQ in the past. It's said to be a measure of "g", which is not much different than saying IQ is a measure of IQ.
IQ and total SAT scores are well-correlated so, at the least, it says something about one's power to handle relatively, but not extremely, complex cognitive tasks like higher math, challenging reading, high-level abstractions, etc. etc. It's about cognitive potential more than anything else. In today's world, cognitive powers matter more than they used to and more than they should, I suppose.
Many psychiatrists and psychologists have learned over the years to estimate peoples' IQs quite accurately, just in conversation. Subtlety of mind, rigor of logic, and curiosity as manifested by breadth and depth of knowledge are some of the markers. Of course, there is the birds of a feather issue too: people tend to find others within a similar range most engaging.
Very high IQ is a life handicap, sad to say. There are few of those, though. Lower IQs which are fully-functional and effective in life are far more common.
Medium-range IQ is the most life-adaptive (ie 110-115) for 95% of things in life from plumbing to software sales to money management. It's often been reported that the ideal IQ for CEOs of large, intricate organizations is near or around 130. Of course, character, personality style, sense of humor, and ability to connect with others in a positive way play perhaps larger overall roles in life although they will not help you perform, or even understand, a regression analysis. Furthermore, even moderately alert managers can easily hire brighter people to carry their water and make them look good. We call that "savvy" or "street smarts," not intelligence.
Here's a good essay on IQ and professional performance.
...a significant percentage of people with IQs over 140 are being systematically and, most likely inappropriately, excluded from the population that addresses the biggest problems of our time or who are responsible for assuring the efficient operation of social, scientific, political and economic institutions.
Lots of awkward nerds there.
Report says schools still shortchanging gifted kids - UI research finds many high-ability children bored and unchallenged, despite increased access to programming
Most public school teachers can rarely keep up with the truly gifted
IQ Science Versus The Cult
IQ and wealth are the two of the main things social justice warriors hate. They sort-of tolerate every other sort of inequality like musical talent or running speed.
